1. Field of the Invention
The present invention is directed to methods and pharmaceutical compositions for administering therapeutic cells to the upper third of the nasal cavity of a mammal, thereby enabling the therapeutic cells to bypass the blood-brain barrier to prevent and/or treat the mammal's damaged and/or degenerating and/or injured central nervous system.
2. Description of the Related Art
Many neurological conditions result from damage to or the loss, i.e., death, of certain cell populations from the central nervous system through aging, disease or injury. The cells damaged or destroyed in these conditions are not intrinsically replaced, thus the central nervous system is damaged and/or degenerating with resulting loss of function. Recent evidence demonstrates that neuronal replacement and partial reconstruction of neuronal circuitry is possible via cell transplantation therapies. Much of the initial work in the field used fetal-cell therapies. More recently, however, it has become evident that the developing and even the adult mammalian nervous system contains a population of undifferentiated, multipotent, neural stem cells that display plastic properties that are advantageous for the design of more effective neural regenerative strategies for many of these neurological conditions.
The neurological conditions, diseases and/or injuries resulting in damaged and/or degenerating CNS, i.e., cell death, comprise Alzheimer's disease, mild cognitive impairment, age-associated memory impairment, Parkinson's disease, cerebrovascular disease including stroke, Creutzfeldt-Jakob disease, familial amyotrophic lateral sclerosis, lewy-body dementia, atherosclerosis, schizophrenia, autism, tardive dyskinesia, multiple sclerosis, seizure disorders, Wilson's disease, progressive supranuclear palsy, Hallervorden-Spatz syndrome, multisystem atrophy, Huntington's disease, familial basal ganglia degeneration, Down's syndrome, cataracts, haemochromatosis, thalassemia, cerebral hemorrhage, subarachnoic hemorrhage, head injury, and spinal cord injury. Moreover, certain medical procedures, for example coronary artery bypass graft (CABG) surgery, are associated with neurological complications that result in damage and/or degeneration of the central nervous system and concomitant cell death. In the case of CABG, the surgery is performed on more than 800,000 patients worldwide each year. Many of the CABG procedures performed are associated with neurological complications. These complications range from stroke in up to 16% of the patients to general cognitive decline with 50% of patients having impairment post-surgery and with progressive decline occurring in some patients over the next five years. In addition, physical and behavioral impairment manifest in some CABG patients. Newman M F et al., N. Eng. J. Med. 344:395-402 (2001); Brillman J., Neurol. Clin. 11:475-495 (1993); and Selnes, O. A., Ann. Thorac. Surg. 67:1669-1676 (1999) are instructive.
Neural stem cells have been demonstrated to replace lost and dying cells and lost neural circuits in the damaged and/or degenerating CNS in cell replacement therapies. For instance, treatment of mice with MPTP, a drug that selectively destroys dopaminergic cells in the brain stem, followed by grafting with a neural stem cell population, resulted in a reconstituted dopaminergic cell population composed of both donor and host cells. Similar studies in mice using a hypoxia-ischemic brain injury model showed transplantation of neural stem cells enhanced the recovery of the damaged system (Park et al. (1999) J. Neurotrauma 16:675-687 and Park et al. (1997) Soc. Neurosci. Abst. 23:346). In patients with stroke, the transplantation of cells from a human neuronal cell line showed improvement of neurological function. (Kondziolka D., et al., (2000) “Transplantation of cultured human neuronal cells for patients with stroke”. Neurology. 55:565-9). In a mouse model of Alzheimer's disease, the transplantation of neural stem cells into the prefrontal and parietal cortices dramatically alleviated the cholinergic deficits and recent memory disruption associated with AD. (Wang, Q., et al., (2006) “Neural stem cells transplantation in cortex in a mouse model of Alzheimer's disease. J Med Invest., 53:61-9).
Further, in Parkinson's disease, the neurons that degenerate in the mammalian central nervous system comprise the dopaminergic neurons of the substantia nigra. Current cell replacement strategies for patients with advanced Parkinson's disease comprise intrastriatal grafts of nigral dopaminergic neurons from 6- to 9-week-old human embryos. Clinical improvements develop gradually over the first 6-24 months after transplantation (Olanow et al. (1996) Trends Neurosci. 19:102-109 and Lindvall et al. (1999) Mov. Disord. 14:201-205). It has been shown that stem cell transplants of different origin, e.g., hematopoietic, embryonic, result in several clinical benefits in patients with severe Parkinson's disease. (Freed, C R, et al. (Transplantation of embryonic dopamine neurons for severe Parkinson's disease. N Engl J Med 2001; 344:710-719).
Similar benefits were realized with progressive multiple sclerosis patients. (Ni XS, et al., (2006) “Autologous hematopoietic stem cell transplantation for progressive multiple sclerosis: report of efficacy and safety at three yr of follow up in 21 patients” Clin Transplant. 20:485-9) (further suggesting that MS treatment should combine immunomodulation with neuroprotective modulaties such as cell-based therapy to achieve maximal clinical benefit).
Further, the first study of human fetus-to-adult striatal transplantation has been performed in three nondemented patients with moderately advanced Huntington disease. Magnetic resonance imaging evaluation at 1 year documented graft survival and growth without displacement of surrounding tissue. All patients improved on some measure of cognitive function. (Kopyov et al. (1998) J. Exp. Neurol. 149:97-108). See also, Date et al. (1997) J. Exp. Neurol. 147:10-17.
Each of the known models and methods for therapeutic cell-based therapies require surgical intervention, i.e., transplantation, of neural stem cells using invasive grafting techniques and/or systemic delivery methods that do not target the damaged areas of the central nervous system. It would be highly advantageous to provide a method, pharmaceutical composition and/or article of manufacture or kit that would provide therapeutic cells, including but not limited to neural stem cells, in a non-invasive and highly targeted manner. For example, it would be advantageous to deliver such therapeutic cells to the degenerating central nervous system in such a way as to avoid systemic exposure. No known method or pharmaceutical composition currently provides such advantages. The present invention provides these advantages by applying the therapeutic cells to the upper third of the nasal cavity, thereby bypassing the blood-brain barrier and administering the therapeutic cells and other compounds directly to the central nervous system.
Certain embodiments of the present invention comprise nasal and/or mucosal antibiotics to assist in protecting the subject patient from nasal bacteria migrating along the neural pathway followed by the applied therapeutic cells and/or pharmaceutical compound. Such antibiotics are well known as applied topically, but none are administered as a pretreatment, co-treatment and/or post-treatement, either systemically and/or intranasally, in conjunction with intranasal application of therapeutic cells and/or pharmaceutical compound.
For example, in one study, mupirocin smeared inside the nose cut infection rates in half or better Staphylococcus aureus is a widely distributed germ that normally resides in the nostrils of an estimated 25 to 30 percent of all hospitalized patients without causing harm. But this bacteria can contaminate surgical sites, causing severe and often deadly infections, especially in people with weakened immune systems.
Another study found that nasal xylitol, an over the counter remedy sold in health food stores, can reduce nasal bacteria and their ability to hold onto and infect cells in the nasal mucosa. Still other studies have found that defensins, a natural antibiotic found in mucosa in the human, can protect against bacterial infection and enhance immune protective function. Mammalian defensins are small, cationic, antimicrobial peptides encoded by the host that are considered to be important antibiotic-like effectors of innate immunity. By using chemokine receptors on dendritic cells and T cells, defensins might also contribute to the regulation of host adaptive immunity against microbial invasion. Defensins have considerable immunological adjuvant activity and linkage of beta-defensins or selected chemokines to an idiotypic lymphoma antigen has yielded potent antitumor vaccines. The functional overlap between defensins and chemokines is reinforced by reports that some chemokines have antimicrobial activities. Although showing similarity in activity and overall tertiary structure, the evolutionary relationship between defensins and chemokines remains to be determined. (De Yang, et al., Mammalian defensins in immunity: more than just microbicidal. Trends Immunol. 2002 June; 23 (6):291-6 12072367).
Moreover, it is well known that regulatory agents comprising trophic and growth factors such as erythropoietin (EPO), brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), fibroblast growth factor (FGF) and epidermal growth factor (EGF) play a crucial role in in-vitro and in-vivo survival and differentiation of stem cells (Erickson et al., Roles of insulin and transferrin in neural progenitor survival and proliferation. J Neurosci Res. 2008 Feb. 21; Bossolasco et al., Neuro-glial differentiation of human bone marrow stem cells in vitro. Exp Neurol. 2005 June; 193(2):312-25). The better survival of surgically transplanted cells was shown in the case of simultaneous application of EPO (Kanaan et al., Exogenous erythropoietin provides neuroprotection of grafted dopamine neurons in a rodent model of Parkinson's disease. Brain Res. 2006 Jan. 12;1068(1):221-9). However, it is not known to introduce such regulatory factors or agents in conjunction with the intranasal application of therapeutic cells and/or pharmaceutical compositions thereof, to the upper third of the nasal cavity, thus bypassing the blood-brain barrier.
In addition, it is well known that regulatory agents comprising various growth factors including insulin-like growth factor-I (IGF-I), nerve growth factor (NGF), and basic fibroblast growth factor (bFGF), regulate the survival and differentiation of nerve cells during the development of the peripheral and central nervous systems. Regulatory agents such as neurotrophins are also required for nerve growth during development (Tucker et al. (2001) Nature Neurosci. 4:29-37). In the mature nervous system, these trophic factors maintain the morphologic and neurochemical characteristics of nerve cells and strengthen functionally active synaptic connections. Such regulatory factors find use in enhancing the methods of cell-replacement therapies according to the present invention.
For instance, bFGF enhances survival and growth of neurons in vitro. Further, bFGF produces a potent growth promoting effect on implanted neurons in vivo when the implanted neurons are genetically engineered to express the bFGF (Takayama et al. (1995) Nat. Med. 1:53-8). In addition, implantation of polymer-based bioactive rods that secrete epidermal growth factor and bFGF into transplanted fetal ventral mesencephalic tissue result in both improved functional characteristics and enhanced cell survival (Tornquvist et al. (2000) Exp. Neurol. 164:130-138).
Nerve growth factor (NGF) has also been shown to influence grafted tissue in the CNS. For example, CHAT activity, an assay indicative of cholinergic cell activity, was elevated significantly in cholinergic neurons that were transplanted into brain tissue that contained an NGF-releasing pellet adjacent to the grafted cells (Mahoney et al. (1999) Med. Sci. 96:4536-4539). IGF-I has also been shown to promote differentiation of post-mitotic mammalian CNS neuronal stem cells and to influence apoptosis of human erythroid progenitor cells. See, for example, Arsenijevic et al. (1998) J. Neurosci. 18:2118-2128; Tanigachi et al. (1997) Blood 90:2244-2252; Reboarcet et al. (1996) J. Biol. Reprod. 55:1119-1125; Muta et al. (1994) J. Clin. Invest. 94:34-43; and, Muta et al. (1993) J. Cell. Phys. 156:264-271. Additionally, it has been shown that certain growth associated proteins, such as, GAP-43 and CAP-23 act to promote regeneration of injured axons and may support regeneration in the spinal cord and CNS. See, for example, Bomze et al. (2001) Nature Neurosci. 4:38-43 and Woolf et al. (2001) Nature Neurosci. 4:7-9.
Administration of regulatory agents as a means of improving the clinical outcome of a mammal having undergone a neural regenerative, i.e., therapeutic cell-based strategy has, however, been meet with difficulty. Generally, these agents cannot be administered systemically. Furthermore, many of these regulatory agents do not cross the blood-brain barrier efficiently. Intracerebroventricular administration, while possibly an effective method for delivering regulatory agents, is an invasive technique that is not preferred in a clinical setting. Implantation of polymers containing regulatory agents is also invasive and is further limited by the relatively small radius surrounding the polymer implant in which the regulatory agent is capable of eliciting an effect. Additionally, while genetic engineering of the transplanted cells to express regulatory agents has been performed, stable transfection and survival of the cells following implantation continues to be problematic.
The present invention provides solutions for, inter alia, these problems.